The luminescence from excitons was detected by a liquid nitrogen cooled charge coupled device (CCD) stanza (Fig. 1a).Excitation intensity dependenceFigure 2a clearly shows that THz pulses with various field strengths induce near infrared luminescence centred around 1.55 eV during QWs at 10 K, favorite central photon energy of the pulse (4 meV) Is about 390 […]